In the manufacture of electrical apparatus, it is often the case that a common platform circuit design is used across a family of devices. Many times the difference is only apparent in instruction code embedded in the devices controller. Two devices having only a difference of instruction code, while physically identical, may operate substantially different. Manufacturers have devised several means of labeling to distinguish one member of a device family from another. Labeling is important for a number of reasons. For one, it lets the manufacturing operation know what version of product is currently being made. Since the products look similar, if not identical, it is important to keep the different versions separated so that customers that order one type of product don't receive something else. Also, when the device is in need of repair, a technician needs some way of knowing what particular product or version of a product he or she is repairing. Labeling is currently performed by one of two primary methods; labeling the housing of the device, placing a label on the circuit board, or a combination of the two. However, there are problems associated with each of these approaches.
In labeling the housing of the device, it is assumed that the circuit or circuit board that is eventually assembled into the housing is the correct one. When the assembly operation is small, and only one or two versions of a product are assembled, this approach works well. However, in high volume, multi-product manufacturing, the chance of a miss-labeling occurring rises dramatically.
By placing a label on the circuit board, the chance of placing an incorrect label on the device drops significantly since the label is put on when the board is assembled. Consequently, the label travels with the board throughout assembly, and it is always clear upon inspection what particular product the circuit board is intended for. However, as devices are packaged to minimize size, setting aside a portion of a circuit board for a label can be costly. It causes the size of the product to be larger, which means fewer products will fit in a given space for shipping. At the very least, placing a label on the circuit board takes up an area that would otherwise be used for circuit components.
Accordingly, it would be advantageous to label a circuit board when it is assembled, and not increase the board size substantially beyond that required only for the circuit components. Therefore there is a need for a labeling method that provides the requisite information with the circuit board, yet requires no additional board area.